Double-acting staking apparatus



Nov. 26, 1963 R|GG|o 3,111,867

DOUBLE-ACTING STAKING APPARATUS Filed Dec. 27, 1961 3 Sheets-Sheet l AIR SUPPLY INVENTOR.

' FRANK L. 1216610 F I6. I BY wn s.

Nov; 26, 1963 F. L. Rleeio 3,111,867

DOUBLE-ACTING STAKING APPARATUS Filed Dec. 27, .1961 3 Sheets-Sheet 2 F I G. 2 I A INVENTOR.

FRANK L. RIGGIO A T TOR Y5.

Unitcd States Patent York Filed Dec. 27, 196i, Ser. No. 164,643 12 Claims. (Ci. 7842.)

This invention relates to apparatus for interconnecting two parts by a staking operation, and more particuiarly to an improved staking press of relatively simple and compact construction which can be operated quickly and easily for mass production.

In the usual staking operation, two metal parts to be joined are placed on a supporting base in an assembled relation in which a detent on one part (the lower part) extends through a hole in the second part (the upper part) and projects slightly above the upper surface of the second part, the detent extending from a shoulder of the first part which engages the second part adjacent the hole. The top of this detent is subjected to a hammer blow applied through a staking punch thereby spreading the metal over the top of the second part around the hole therein. Such a staking operation requires holding the parts together in their assembled relation prior to the staking blow, and application of the hammer blow to the staking punch while it is accurately aligned with the detent.

In Riggio et al. Patent No. 2,941,428, dated June 21, 1960, there is disclosed an apparatus by which the steps incident to the usual staking operation can be performed easily in rapid succession. kill that apparatus, a hollow pressing punch is slidable vertically in a section of a a stationary frame overlying the frame base and has a lower end engageable with the assembly to be staked to hold it in position on the base. A staking punch is slidable in the pressing punch and has a lower end adapted to engage the detent of the lower part of the assembly when the latter is engaged by the pressing punch. A hollow ram is movable vertically in the upper section of the frame and contains an air cylinder, and actuating means are operatively connected to the ram for urging it downward to press the pressing punch against the assembly on the base,

thereby holding the parts firmly together in their assembled relation. A piston is slidable vertically in the air cylinder in the ram and is engageable at its lower end with the upper end of the staking punch, the piston being urged upwardly in the cylinder by a biasing means. A compressed air line is connected through a valve to the upper portion of the air cylinder. Thus, by operation of this valve to admit compressed air into the cylinder, the piston is actuated downwardly against the biasing means and is thereby impacted against the upper end of the staking punch, whereby the latter is hammered downwardly in the pressing punch and against the detent of the assembled parts when the assembly is held by the pressing punch.

The apparatus disclosed in said Riggio et al. patent is operated first by manually depressing the ram through its actuating means to urge the pressing punch against the assembly on the base and then by manually actuating the valve for admitting compressed air to impact the piston against the upper end of the staking punch, while the ram is held down manually.

An object of the present invention is to provide a staking apparatus in which the pressing and staking steps are performed automatically once the apparatus is started in operation.

Another object is to provide such an apparatus having means coordinated with the pressing and staking operations for automatically ejecting the staked parts from the apparatus in preparation for the next cycle of operations.

3,111,857 Patented Nov. 25, 1%63 A staking press made according to the present invention comprises a punch holder, a staking punch slidably mounted in the holder, a Work holder adapted to sup port the assembly of parts (to be staked together) in opposed spaced relation to the punch holder, and a pair of pistons each slidable in a corresponding piston chamber, the first piston being operatively connected to one of the holders and advanceable in the first piston chamber toward the other holder to compress the assembly of parts between the two holders, the second piston being advanceable in its chamber to hammer the punch against one of the parts on the work holder so as to effect the staking operation while the assembly is thus compressed.

According to one feature of the invention, the two pistons are operable from a compressed air line in such a manner that the second piston is not advanced to hammer the punch until the first piston has compressed the assembly of parts between the punch and work holders, at which time the air pressure in the first piston chamber reaches a predetermined high value sufiicient to operate an actuator for opening :a valve which admits compressed air from the line into the second piston chamber, thereby advancing the second piston to hammer the punch and effect staking operation.

In the preferred form of the new staking apparatus, the work holder is operatively connected to the first piston so that the assembly of parts to be staked together is in effect supported by the first piston. Thus, by opening of a valve in the compressed air line, compressed air is admitted to the first chamber to advance the first piston and thereby move the assembly of parts against the punch holder. In this preferred embodiment, the supply valve for admitting compressed air into the second piston chamber (containing the punch-hammering piston) is opened by a pneumatically operable actuator connected through an air duct to the first piston chamber. When the first piston has been advanced to compress the assembly of parts against the punch holder, the air pressure in the first piston chamber builds up to a predetermined high pressure conresponding substantially to the air pressure in the supply line, whereupon this high pressure communicated through the air duct to the pneumatic actuator causes the latter to open the supply valve and effect the punch-hammering operation by the second piston under the air pressure in the line.

The above-noted preferred embodiment of the invention is well suited for use of an ejector operable automatically to remove the assembly of parts from the apparatus after the staking operation. That is, after the first piston has advanced the assembly into staking position against the punch holder, an ejector may be advanced into the return path of the assembly so as to remove the latter from the first piston as the latter retracts after the staking operation, whereupon the ejector may be re tracted to eject the staked assembly in preparation for the next staking operation. If such an ejector is used, its advancing and retracting movements may be effected pneumatically from the compressed air line in timed relation to the advancing and retracting movements of the first or work holding piston.

For a better understanding of the invention, reference may be had to the accompanying drawings, in which:

FIG. 1 is a vertical sectional view, partly in elevation, of a preferred form of the new staking apparatus, showing the compressed air line connections, the parts being illustrated in the positions which they assume at the moment of impact of the stacking punch;

FIG. 2 is an elevational view of the apparatus shown in FIG. 1, as viewed from the left in FIG. 1 but with the lower part of the apparatus broken away;

FIG. 3 is a plan view of the upper part of the apparatus illustrated in FIGS. 1 and 2, showing a valve assem- 3 bly including the air supply valve for the punch-hammering piston and the pneumatic actuator for this valve; and

FIG. 4 is a sectional view on the line 44 in FIG. 3.

The apparatus as illustrated comprises a frame having a base 18 forming a table 16a and having a pair of spaced uprights l111a extending upwardly from the table at opposite sides thereof. The uprights 11 support an upper section 12 of the frame which is is spaced above the table 16a.

The frame base constitutes a stationary member defining a cylindrical chamber 14 in which a first piston 15 is slidable vertically. Piston 15 carries an axial rod 16 extending downwardly through a bottom plate 17 bolted to the base 1%. Plate 17 forms a closure for piston chamber 14 at its lower end and has a downwardly extending hollow boss 17a into which the piston rod 16 projects with a clearance. A hollow cap 13 is screwed into the lower end of boss 17a and is adapted to receive the lower part of rod 16, this cap being closed at its lower end by a head 18a. A steel ball 19 rests on the conical bottom of the cap interior and forms a bearing surface for rod 16 when the piston 15 is in its lowermost position. It will be understood that the piston rod 16 has a sliding sealed fit in the bottom plate 17 to prevent escape of air pressure from piston chamber 14.

Piston 15 is urged to its lowermost position by a biasing element in the form of a compression spring 20 coiled around the upper part of the piston. Spring 20 bears at one end against the piston and at its opposite end against the overlying table portion 100. Normally, the spring 2% holds the piston and its rod 16 down against the ball 19. By screwing the cap 18 upwardly or downwardly in the hollow boss 17a, the ball 19 will be raised or lowered to adjust the lowermost position of piston 15. The cap 18 may be locked in its adjusted position by a nut 18b.

The bottom plate 17 is provided with a passage 22 forming an air inlet opening into piston chamber 14 below the piston. A compressed air supply source 23 is connected through pipe line 24 to the inlet passage 22, the pipe 24 having a control valve 25. The valve 25 has a rotor 26 which, in the on position shown in FIG. 1, allows flow of compressed air from source 23 to piston chamber 14 while closing an air vent 27 of the valve. However, when rotor 26 is turned 90 counterclockwise in FIG. 1 to its off position, it cuts ofi the supply of compressed air from source 23 and connects piston chamber 14 to the air vent 27. As will be pointed out presently, the valve 25 is moved to its on position to initiate the pressing and staking operations and is moved to its off position to return the parts of the apparatus to their normal positions. Such movements of the valve 25 may be effected by a solenoid under control of a switch (not shown) mounted at any location convenient to the operator of the apparatus.

The part of chamber 14' above piston 15 is vented to atmosphere through an opening in table 100, and through this opening extends a post 3%) releasably connected to the upper end of piston 15. Post 30 serves as a work holder and is in effect a part of this piston. An adapter 31 is releasably secured in the table opening and serves to guide the post 30, which extends through the adapter with a sliding fiit. Work pieces of different sizes or configurations may be accommodated by substituting a different post 39 and a corresponding adapter 31 tor the post and adapter as shown.

For illustrative purposes, the post or work holder 3% is shown in a form suitable for supporting a shaft S to which a gear G is to be staked, the shaft resting at its lower end on the top of post 3%) and having an axial opening which closely receives a pin 3% projecting from the top of the post. At its upper end, the shaft S has a reduced portion extending through a central opening in gear G which rests on the resulting shoulder of the shaft, it being understood that the work parts are to be staked together by upsetting the metal of the reduced portion of the shaft located in the central gear opening.

The upper frame section 12 includes a vertical cylinder body 33 directly overlying the work holder 30. Cylinder 33 forms a second piston chamber 34 in which a second piston 35 is slidable vertically. Piston 35 has a depending rod 35a and is urged upwardly in cylinder 33 by a compression spring 36 coiled around rod 35a. The uppc rend of spring 36 bears against the lower end of piston 35, while the lower end of spring 35 bears against a shoulder in chamber 34.

A staking punch 37 is slidable vertically in a punch holder 38 releasably secured to the lower portion of cylinder 33. As shown, the punch holder 38 has a shoulder bearing against the bottom of cylinder 33, the reduced portion of the punch holder above this shoulder being closely received in the lower portion of piston chamber 34. A set screw 39 releasably secures the punch holder to cylinder 33 and allows its replacement by a substitute holder for accommodating a different form or size of the punch 37.

The staking punch 37 has a close sliding fit in an axial bore of the holder 33, the upper part of this bore being enlarged as shown at 38a to receive the head 37a of the punch. With the pistons 15 and 35 retracted by heir springs Ztt and 36, the punch head 37a rests on the shoulder at the bottom of bore enlargement 33a, so that the lower end of punch 37 projects through the bottom of holder 38. When the first piston 15 is raised upon movement of valve 25 to its on position, the upper end of shaft S engages the bottom of punch 37 and raises the latter to the position shown in FIG. 1, the piston 15 pressing the gear G against the bottom of punch holder 38 so that the work parts G-S are compressed between the holders 30 and 38. With the work parts thus compressed compressed air is admitted into the top of piston chamber 34, as will be described presently, to drive piston 35 and its rod 35:: downwardly against the punch head 37a, thereby hammering the pointed lower end of the punch against the reduced upper end of shaft S to effect the staking operation in a manner well known in the art.

The piston chamber 34 is adapted to receive compressed air through a cap 41 containing a valve assembly, as shown particularly in FIGS. 3 and 4. As there shown, the cap comprises a valve housing 42 releasably secured to the upper end of cylinder 33 by machine screws 42a. The housing 42 has a horizontally elongated cylindrical bore 43 provided with an enlargement in which a cylindrical insert 44 is secured. The insert 44 forms a piston chamber 44a in which a piston valve 45 is slidable. At one end, the piston valve 45 carries. an impact rod 46 having a close sliding fit in a reduced extension of piston chamber 44a. A vent hole 44b in the housing extends upwardly from this reduced extension of chamber 44a. An air supply valve member 47 is engageable by the reduced end 4641 of rod 46 and is normally urged against a seat 4-8 by a compression spring 49 in the reduced bore portion 43. Valve 47 has an axial stem 47a which is slidable in a small guiding bore opening into bore 43. The seat 48 for valve 47 is at the inner end of insert 44; and when valve 4-7 is seated by its spring 49, it prevents flow of air from the reduced bore portion 43 into the reduced part of bore 44a in the insert 44.

The valve housing 42 has an air inlet passage 5 leading into the reduced bore portion 43. Passage 51 communicates with the compressed air source 23 through a pipe line 52 (FIG. 1), the compressed air lines 24 and 52 branching from the compressed air supply 23. Thus, the reduced bore portion 43 is under the full air pressure from source 23, which supplements the action of spring 49 in holding the supply valve 47 closed. However, when piston valve 45 is moved to the right in FIG. 4, it unseats the supply valve 47 to allow flow of compressed air into the insert 44 and downward through an outlet passage 53 into the piston chamber 34. At the same time, the enlarged portion of impact rod 46, in advancing with piston valve 45, closes the air vent 44-11. As will be pointed out presently, the piston valve 45 is part of a pneumatically operable actuator for opening the air supply valve 47 to admit compressed air into the punchhammering cylinder 33.

A hollow body 55 is screwed into the open end of the enlargement of bore 43. A hollow insert 56 in this enlargement is clamped between the insert 44 and the hollow body 55 and forms a seat 57 for the piston valve 45. The insert 56 has an axial cylinder bore 58 leading through the seat 57. An air inlet passage 59 in housing 42 leads to an annular space surrounding the insert 56 and which communicates with bore 58 through radial passages 61 The inlet passage 59 is connected by a pipe duct 61 to the compressed air pipe line 24 at a part of this line located between controlling valve 25 and the first piston chamber 14. Thus, the pressure in chamber 14 will be communicated through duct 61 and passages 59 and 6t} to bore 58 where the pressure acts upon the outer or left-hand end of piston valve 45 as viewed in FIG. 4.

A red 63 projects axially from the outer end of piston valve 4 5 and extends through bore 5% with a clearance and through the hollow body 55. A sealing 64 is mounted in the inner end of body 55 and closely surrounds rod 63 to prevent escape of pressure from bore 5%. An adjustable bushing 65 is screwed into the outer end of body 55 and has an axial bore through which rod 63 projects. A compression spring as is coiled around rod 63 and is seated at one end on a shoulder in bushing 65 and at the opposite end against a knob 67 on the outer end of rod 63. Spring 66 constitutes a biassing element urging piston valve 45 out-ward against its seat 57; and by adjusting the threaded bushing 65 in body 55, the outward biassing force on piston valve &5 may be adjusted. The bushing 65 may be locked in its adjusted position by a nut 68. Prior to the pressing and staking operations, the control valve 26 is in it Off position so that the first piston chamber '14 and the bore 58 in valve housing 42 are vented to atmosphere through vent 27. As a result, spring 29 holds the first piston in its lowermost position where its rod 16 bears on the ball 19, while spring 36 holds the punch-hammering piston 35 in its uppermost position against valve housing 42. Also, piston valve 45 (FIG. 4) is held by spring 66 in its retracted position against seat 57, whereby the air supply valve 47 is held closed against its seat 48 by spring 49 and the air supply pressure in the reduced bore portion 43. Consequently, the space above the piston 35 is vented to atmosphere through passage 53 and vent opening 44-12.

To initiate the pressing and staking operations, valve 25 is turned to its 011 position, whereupon compressed air entering chamber 14- raises piston 15 rapidly against its spring 24} to press the work assembly GS against the bottom of punch holder 38 as previously described, thereby raising the punch 37 to the position shown in FIG. 1. However, as long as piston 15 is moving upwardly and thereby expanding the confined air space at the outlet end of valve 25, the air pressure in bore 58 is insuilicient to unseat piston valve 45 against the action of its spring 6-6, it being observed that the air pressure in bore 58 acts on only a small annular area of piston valve 45 as long as the latter is held against its seat 57. When the workholding piston 15 reaches the upper limit of its advancing movement, where it holds the work assembly under pressure from air supply 24, the full pressure of the air supply is rapidly communicated through duct 61 to the bore 53 and acts to overcome the biassing action of spring 66. Upon the resulting unseating piston valve 45, the high pressure in bore 58 acts on a substantially larger etfective area of the piston valve so that the latter is advanced rapidly to the right (FIG. 4) to impact the reduced end 46a of rod 46 against air supply valve 47.

Therefore, the latter valve is opened against the action of spring 49 and against the high air pressure in the reduced bore portion 43, it being noted that the latter pressure acts against a relatively small area of valve 47 as compared with the affected area of piston valve 45 against which the opposing pressure from bore 58 acts.

The air supply valve 47 will thus be held in its open position so that pressure from air line 52 is exerted on top of piston 35 through passage 53. As a result, piston 35 is driven downwardly against its spring 36 to hammer the staking punch 3'7 against the compressed work assembly GS as previously described. This completes the compressing and punching operations.

Control valve 25 is then returned to its Off position so as to vent the compressed ah" lines 24 and 61 to atmosphere. As a result, piston vid is returned to its 10v ermost position to withdraw the staked work assembly GS from punch holder 33. At the same time, the exhaust from bore 58 (by way of passages 59 and 60, duct 61 and vent 27) allows spring 66 to retract piston valve 4-5 against its seat 57, thereby opening air vent 44b and causing air supply valve 47 to return to its normally closed position against seat 48. Thus, the punch-hammering piston 35 is returned by its spring 36 to its uppermost position, the air above this piston exhausting through passage 53 and vent 44b. Upon removal of the staked-assembly GS from the retnacted work carrier 39, the apparatus is ready for the next pressing and staking operations.

As will be apparent from the foregoing, the control valve 25 in compressed air pipe line 24 constitutes a means for admitting compressed air to the first piston chamber 14 to advance the firstpiston 15 toward punch holder 33, and the cap valve assembly 41 communicating with piston chamber 14 through duct 61 constitues a means responsive to compression of the work assembly between first piston 15 and punch holder 3% for admitting compressed air to cylinder 34 to impact the second piston 35 against punch 37 and thereby effect the staking operation.

The apparatus, "as illustrated also includes an ejector for automatically removing the assembly of work parts from the apparatus after the pressing and staking operations. As shown in FIGS. 1 and 2, the ejector comprises a fork having two spaced parallel tines 7t) interconnected at their rear ends by a U-shaped member 71. The tines 70' are adapted to straddle the shaft S of the work assembly while supporting the gear G on the upper surfaces of the tines. Thus, when fork 70-71 is tilted clockwise in FIG. 1 the staked-assembly GS is adapted to slide downwardly and to the right along the fork and over the rear end thereof into a receptacle (not shown), the lower end of the shaft S clearing the underlying bottom of U-shaped member 71. The ejector fork 7tl71 is pivotally mounted intermediate its end between a pair of uprights 72 on a slide 73. The bottom of slide 73 is provided with a dove-tail 73a slidable in a mating track 7 4a in the upper surface of a hollow block 74 secured to table it? Slide 73 is reciprocable toward and away from work holder 34 by a piston 75 slidable in a cylinder 76 mounted on table ltla below track 74a. A throttle valve 77 connects one end of cylinder 76 to the compressed air duct 61, and the piston 75 has a rod 78 extending through the other end of cylinder 76. At its outer end, rod '78 has an upturned portion projecting through a slot in the bottom of track 74a and connected to slide 73. A compression spring 79 in cylinder 76 urges piston 75 toward its retracted position (to the right in FIG. 1), in which posit-ion the slide 73 and [fork 7d are retracted from work holder 30.

Upon movement of control valve 25 to its On position there is a delay in the advance of ejector piston 75 due to the throttling action of valve 77. However, shortly after piston 15 has pressed the work assembly against punch holder 38, the air pressure in cylinder 76 will be sufficient to overcome the action of spring 79 and advance the slide 73 to the forward end of track 74a, whereby the fork 79 is moved into straddling relation to shaft S directly under gear G as shown in P16. 1. Conequently, when control valve is turned to its Oil position, the retraction of work holder 3% will lower the Work assembly so that the lower face of gear G rests on top of the fork tines 7t whereupon further lowering of the work holder disengages pin 3% from shaft S. The staked-assembly GS will thus be removed from work holder and placed on fork 7% before latter is retracted to any substantial extent, because the throttling action of valve 77 delays the exhaust of compressed air from cylinder 7d through duct 61 and vent 27 of valve 25.

The fork tines 7% have depending cars 81 through which the fork is pivotally mounted between the slide uprights 72. A detent on each ear is engageable with a stop 72a on the adjacent upri -t '72. Tension springs $3 are connected between each u prignt 72 and the outer portion of the adjacent tine so as to urge de-tents 82 against their stops 72a. As the slide 73 and fork 7-9 retract under the action of compression spring 79 (cylinder 76 now being, vented through throttle valve 77 and the control valve vent 27), the fork is tilted clockwise in FIG. 1 against the action of tension springs 83 by a cam be secured to block 74 and acting on a follower 85 projecting laterally from one of the tines 7 As a result, after the forward end of 'ector fork 7d-7El has been retracted from beneath the punch holder 38, the tilting of the fork by cam causes the staked-assembly G-S to slide downwardly on the fork and over its rear end into the receptacle (not shown). As the slide 73 advances. from its retracted position, on completion of the next pressing and staking operations, cam 34. allows tension springs 83 to return the fork to its horizontal position before it reaches its advanced position under punch holder 38.

I claim:

1. A staking press for interconnecting two assembled parts, which comprises a first piston for supporting the assembly of parts, a stationary member defining with said first piston a fluid chamber for receiving compressed air to advance the piston, a cylinder mounted opposite said first piston, a punch holder supported by the cylinder and against which said assembly is adapted to be pressed by said advance of the first piston, a staking punch slidable in said holder and engageable at one end with one of said assembly parts on the first piston, a second piston slidable in said cylinder and engageable with the other end of the punch, the second piston being biased away from the punch and said first piston, first means for admitting compressed air to said chamber to advance the first piston toward the punch holder, and second means responsive to compression of the assembly between said first piston and the punch holder for admitting compressed air to said cylinder to impact the second piston against the punch, thereby hammering the punch against said one part of the assembly on the first piston.

2. A staking press according to claim 1, comprising also releasable means for securing the punch holder to said cylinder.

3. A staking press according to claim 1, comprising also a spring biasing the second piston away from the punch and the first piston.

4. A staking press according to claim. 1, in which said first means include a first compressed air pipe line leading to said chamber, and a control valve in said pipe line, said second means including a second compressed air pipe line leading to said cylinder, a nornally closed supply valve in said second line, and a device operable to open said supply valve in response to a predetermined high pressure in a portion of said first line between the chamber and said control valve.

5. A staking press according to claim 1, in which said first means include a first compressed air pipe line leading to said chamber, and a control valve in said pipe line, said second means including a second compressed air pipe line leading to said cylinder, a normally closed supply valve in said second line, and a device operable to open said supply valve in response to a predetermined high pressure in a portion of said first line between the chamber and said control valve, said pressure responsive device comprising a pneumatically operable actuator, a biasing element holding the actuator in a retracted position, and a duct connecting the actuator to said portion of the first air line and through which said predetermined high pressure is operable against the biasing element to advance the actuator for opening the supply valve.

6. A staking press according to claim 1, in which the first piston is biased toward a retracted position, said first means including a compressed air pipe line leading to said chamber, and a control valve located in said line and provided with an air vent, the control valve having a first position in which it connects the chamber to said vent while cutting off air fiow through the line and also having a second position in which it allows air flow through the line while closing the vent, where-by return of the control valve from its second to its first position causes the first piston to retract the assembly of parts from the punch holder.

7. A staking press according to claim 1, in which the first piston is biased toward a retracted position, said first means including a compressed air pipe line leading to said chamber, and a control valve located in said line and provided with an air vent, the control valve having a first position in which it connects the chamber to said vent while cutting ofi air flow through the line and also having a second position in which it allows air flow through the line while closing the vent, whereby return of the control valve from its second to its first position causes the first piston to retract the assembly of parts :from the punch holder, said second means including a second compressed air pipe line leading to said cylinder, a normally closed supply valve in said second line, a pneumatically operable actuator movable to an advanced position for opening the supply valve by a predetermined high air pressure in a portion of said first line between the chamber and said control valve, and a biasing element holding said actuator in a retracted position against air pressures in said portion which are less than said predetermined high pressure, whereby movement of the control valve to its second position causes the actuator to open the supply valve after said advance of the first piston, and return of the control valve to its first position allows said biasing element to retract the actuator and thereby close the supply valve.

8. A staking press according to claim 1, in which the first piston is movable to a retracted position to withdraw said assembly from the punch holder, the press comprising also an ejector, and means operable in timed relation to said advancing and retracting movements of the first piston for actuating the ejector to remove said assembly from the first piston.

9. A staking press for interconnecting two assembled parts, which comprises a punch holder, a punch slidable in said holder, a piston for supporting the assembly of parts and movable relative to the holder, means vfor moving the piston in one direction to advance the assembly thereon to said holder and press the assembly aga'mst the holder, the piston being movable in the opposite direction to withdraw the assembly from the holder, and means operable in response to said pressing of the assembly against the holder for hammering the punch relative to the holder and against one of said parts of the assembly on the piston.

10. A staking press according to claim 9, comprising also an ejector, and means operable in response to said piston movements for reciprocating the ejector into and out of the path of said assembly withdrawal, to remove the assembly from the piston.

11. A staking press for interconnecting an assembly of two parts, which comprises a punch holder, a staking punch slidably mounted in the holder, a work holder adapted to support said assembly of parts in opposed spaced relation to the punch holder, first and second pistons slidable in first and second piston chambers, respectively, said first piston being operatively connected to one of said holders and advanceable in said first chamber toward the other holder to compress said assembly between the holders, the second piston being advanceable in its chamber to hammer the punch against one of said parts on the work holder, a com ressed air line, a control valve operable to admit compressed air from said line into the first chamber to advance said first piston and thereby efi'ect said compression of the assembly, whereby the air pressure in said firs-t chamber builds up to a predetermined high pressure corresponding substantially to the air pressure in said line, a supply valve connecting the compressed air line to said second chamber, the supply valve being normally closed but movable to an open position for admitting compressed air to the second chamber to advance the second piston, and an actuator operative-ly connected to said first chamber and responsive to said high pressure therein for actuating said supply valve to its open position.

12. A staking press for interconnecting an assembly of two parts, which comprises a punch holder, at staking punch slidably mounted in holder and having a Working end and a striking end, a Work holder adapted to support said assembly of parts in opposed spaced relation to the punch holder and said Working end of the punch, a cylinder forming a piston chamber, a piston slidable in said cylinder and movable into and out of engagement with said striking end of the punch, actuating mechanism for moving one of said holders toward the other to press the punch hoider and the parts assembly together, a compressed air line leading to the piston chamber, a valve in said line having an operating position for supplying the chamber with compressed air to hammer the piston against said striking end of the punch and thereby drive said working end into the assembly, the valve also having a non-operating position for cutting off said admission of air, and means operatively connected to the valve and responsive to said pressing-together movement of said one holder for moving the valve to its said operating position.

No references cited. 

1. A STAKING PRESS FOR INTERCONNECTING TWO ASSEMBLED PARTS, WHICH COMPRISES A FIRST PISTON FOR SUPPORTING THE ASSEMBLY OF PARTS, A STATIONARY MEMBER DEFINING WITH SAID FIRST PISTON A FLUID CHAMBER FOR RECEIVING COMPRESSED AIR TO ADVANCE THE PISTON, A CYLINDER MOUNTED OPPOSITE SAID FIRST PISTON, A PUNCH HOLDER SUPPORTED BY THE CYLINDER AND AGAINST WHICH SAID ASSEMBLY IS ADAPTED TO BE PRESSED BY SAID ADVANCE OF THE FIRST PISTON, A STAKING PUNCH SLIDABLE IN SAID HOLDER AND ENGAGEABLE AT ONE END WITH ONE OF SAID ASSEMBLY PARTS ON THE FIRST PISTON, A SECOND PISTON SLIDABLE IN SAID CYLINDER AND ENGAGEABLE WITH THE OTHER END OF THE PUNCH, THE SECOND PISTON BEING BIASED AWAY FROM THE PUNCH AND SAID FIRST PISTON, FIRST MEANS FOR ADMITTING COMPRESSED AIR TO SAID CHAMBER TO ADVANCE THE FIRST PISTON TOWARD THE PUNCH HOLDER, AND SECOND MEANS RESPONSIVE TO COMPRESSION OF THE ASSEMBLY BETWEEN SAID FIRST PISTON AND THE PUNCH HOLDER FOR ADMITTING COMPRESSED AIR TO SAID CYLINDER TO IMPACT THE SECOND PISTON AGAINST THE PUNCH, THEREBY HAMMERING THE PUNCH AGAINST SAID ONE PART OF THE ASSEMBLY ON THE FIRST PISTON. 